Toxic Plants for Goats
Knowing toxic plants for goats is a helpful skill. This article references the Goat Digestive System Article. If you haven’t already, take a second to check it out to better understand how certain toxins affect goat health. First, this list of toxins and toxic plants is by no means exhaustive. Also, the goal of this article is to provide an overview understanding of the most common toxins and their effects.
We all know goats don’t eat just anything. However, there are several plants that do pose health risks to goats. Some of these harmful plants are more common than others, and a few can be found in the pasture. For goat packers, it can be common to find several of these plants on trail. It is helpful to be able to identify the plants in your area or the areas you pack with goats. Especially for pack goats, identifying these plants is important as goats are usually foraging 100% of their feed while in the back country.
Goats are Good at Caring for Themselves
It’s important to note that goats do have active immune and digestive systems that can be relatively resilient to many toxins in low exposure. However, concentrated toxins can be harmful or deadly. It’s also important to remember that goats generally have great instincts when it comes to harmful plants. Goats avoid eating harmful plants unless little else is available or out of curiosity when plants are first encountered.
Most toxic plants are unpalatable and are very unlikely to be eaten. Many toxins that are ingested are often diluted if other quality feed is available limiting the severity of their effects. However, toxins like cyanides and some alkaloids or glycosides such as Japanese Yew and Oleander are severe and often fatal. Special care should be taken on pasture that is overgrazed and more prone to invasive species. Care should also be taken in springtime; toxic invasives often sprout first before native graze plants abound.
Types of Toxic Plants for Goats
Cyanogenic Glycoside (cyanide) – This toxin makes hemoglobin less able to deliver oxygen to tissues. Signs and symptoms often appear rapidly and include difficulty breathing, excitement, tremors, gasping, dilated pupils, bright pink mucous membranes, bloat, staggering, involuntary urination and defecation, convulsions, coma and death due to asphyxiation. Treatment for cyanide is sodium nitrite or sodium thiosulfate however most animals die before treatment is available.
Other Glycosides – There are many types of glycosides however most have similar signs and symptoms; some are less dangerous than others. Signs and symptoms include severe vomiting and diarrhea, swollen and inflamed oral tissues, cold extremities, dilated pupils, increased heart rate, weakness and death.
Alkaloid Toxins – There are many types of alkaloid toxins. Signs and symptoms include vomiting, diarrhea, bloat, weakness, nervousness, trembling, difficulty breathing, incoordination, dilated pupils, decreased heart rate, convulsions, coma and death due to cardiac standstill.
Nitrate Toxins – Several Nitrates exist, but when nitrates are digested they breakdown to nitrites which bond with hemoglobin which blocks oxygen delivery to tissues. Signs and symptoms include tremors, increased but weak pulse, decreased temperature, weakness, staggering, difficulty breathing, discolored mucous membranes, nervousness, frequent urination, diarrhea, collapse, coma and death; surviving animals may abort. Blood of affected animals is dark red or brown. Nitrate toxicity may be treated by veterinary treatment of methylene blue.
Oxalate Toxins – Ruminants tend to be more resistant than monogastrics to oxalates. Ruminants can however be affected when the majority of their grazing is made up of oxalate plants such as greasewood. Oxalate toxins can cause swollen kidneys, bleeding in the rumen wall, and fuid in the abdominal cavity. Signs and symptoms can include weakness, depression, weak pulse, gastrointestinal paralysis, salivation, vomiting, diarrhea, difficulty breathing, coma and death.
Lactone/Helenalin Toxins – The primary culprit of this toxin is sneezeweed. This is a mild toxin that may become severe if no other forage is available over time. Signs and symptoms include wasting, depression, profuse vomiting, salivation, stiffness, weakness, secondary pneumonia and death. No treatment exists but animals may recover from early detection and removal from the source.
Enzyme Toxins – Enzyme toxins are somewhat unique in the sense that they destroy necessary nutrients. These toxins essentially create an abnormal nutrient deficiency of vitamins and or minerals. Thanks to the ruminant digestive system, many enzyme toxins are greatly neutralized by the production of vitamins from nitrogen in the digestive process. Some however carry carcinogens as well that cause tumors typically in the bladder.
Cicutoxin – Hemlocks like poison hemlock and water hemlock are most common for this toxin. The concentration of this toxin is in the roots and creates a strong carrot odor. Cicutoxins are potent and fast acting. Signs and symptoms include rapid respiration and pulse, dilated pupils, drooling, muscle tremors, convulsions and coma, culminating in death from asphyxiation.
Toxalbumin – Black Locust is the primary toxin containing plant. Signs and symptoms of taxalbumin include lack of appetite, diarrhea, weakness, depression, founder, weak pulse, hindquarter paralysis, cold extremities, dilated pupils and colic. Death from taxalbumin is rare, no treatment exists and it is a slow recovery.
Hypericin – Hypericin is a photosensitizing toxin meaning it is made worse by exposure to sunlight. Unpigmented skin becomes inflamed and itchy and large areas may slough. They may also go blind, convulse and die. St. Johnswort is the primary plant.
Gallotannin – Oaks are most well known for carrying tannins. Tannins are most concentrated in young leaves, and green acorns. Tannins affect the kidneys and gastrointestinal system. Signs and symptoms of gallotannin toxins include poor appetite, emaciation, constipation followed by diarrhea, frequent urination, depression, excessive thirst and death. Mild cases may be treated with calcium hydroxide. This may also be used preventatively if oaks cannot be avoided. Also, thanks to the ruminant digestive system, goats can neutralize mild tannins though high concentrations can still pose a risk.
Resin Toxins – Resin toxins make up a smaller group of toxins generally presenting with signs and symptoms including incoordination, salivation, bloat, weakness, muscle spasm, coma, and death. Animals may be found down, unable to stand, with their heads weaving from side to side.
List of Known Toxic Plants for Goats
- Wild Cherry
- Black Cherry
- Cherry Laurel
- Plants with Pitted Fruits
- Clovers – when fresh
- Oleander – extremely toxic
- Hemp Dogbane
- Japanese Yew – extremely toxic
- Tansy Ragwort
- Yellow Jessamine
- Stagger Grass (Fly Poison)
- Yarrow (Mild Gastrointestinal Irritant)
- Mustard family
Most of these cultivar (food) species have been developed to have reduced toxins and are generally safe to feed livestock.
- Clovers – when fresh, dry is neutral
- Milk Thistle
- Bracken Fern
- Water Hemlock
- Poison Hemlock
- Black Locust
- St. Johnswort
- Oak Trees/Acorns/Leaves
- Tall Fescue
- Black Walnut
- Ponderosa Pine (mostly for cattle)
- False Hellebore
- Prickly lettuce
- Russian Knapweed
- Yellowstar Thistle
- Spurge Laurel
- Coffee senna
- Bracken Fern – carcinogen and causes bone marrow paralysis
- Sweet Clover/White Sweet Clover – toxic when harvested or as silage, neutral fresh.
- Also beware of pesticides, herbicides, and fertilizers
- Cultivated grasses and grains can cause photosensitization and accumulate toxic levels of nitrates especially after fertilization. Seeds can also cause irritation and become entrapped in the throat and airways. Seeds and grains are also prone to toxic molds. These feeds should be silaged before feeding.
For more information:
Washington State University: https://search.wsu.edu/default.aspx?cx=013644890599324097824:kbqgwamjoxq&cof=FORID%3A11&q=toxic+plants&sa=Search
WSU Identification of Toxic Plants for Livestock Manual: https://s3.wp.wsu.edu/uploads/sites/2054/2014/04/Protect-Your-Horses-Livestock-From-Toxic-Plants.pdf
Oregon State University Small Farms: Poisonous Plants Commonly Found in Pastures: https://extension.oregonstate.edu/pests-weeds-diseases/weeds/poisonous-plants-commonly-found-pastures
University of Arkansas, University of Georgia, North Carolina State University joint publication:
Tennessee Agricultural Extension: https://extension.tennessee.edu/Giles/Documents/Poisonous%20Plants%20of%20the%20Southeastern%20United%20States.pdf